renown (n.) c. 1300, from Anglo-French renoun, Old French renon "renown, fame, reputation," from renomer "make famous," from re- "repeatedly" (see re-) + nomer"to name," from Latin nominare "to name" (see nominate). The Middle English verb reknouen "make known, acknowledge" has been assimilated to the noun via renowned. In old German university slang, a reknowner (German renommist) was "a boaster, a swaggerer." http://www.etymonline.com/index.php?term=renown know (v.) Old English cnawan (class VII strong verb; past tense cneow, past participle cnawen), "to know, perceive; acknowledge, declare," from Proto-Germanic*knew- (cognates: Old High German bi-chnaan, ir-chnaan "to know"), from PIE root *gno- "to know" (cognates: Old Persian xšnasatiy "he shall know;" Old Church Slavonic znati, Russian znat "to know;" Latin gnoscere; Greek *gno-, as in gignoskein; Sanskrit jna- "know"). Once widespread in Germanic, this form is now retained only in English, where however it has widespread application, covering meanings that require two or more verbs in other languages (such as German wissen, kennen, erkennen and in part können; French connaître, savoir; Latin novisse, cognoscere; Old Church Slavonic znaja, vemi). The Anglo-Saxons used two distinct words for this, witan (see wit) and cnawan.
http://www.etymonline.com/index.php?term=know
Does that mean not related?